The following is a summary of “Glymphatic function from diffusion-tensor MRI to predict conversion from mild cognitive impairment to dementia in Parkinson’s disease,” published in the June 2024 issue of Neurology by Pang, et al.

Parkinson’s disease (PD) is associated with brain glymphatic dysfunction and cognitive decline, but the long-term impact on cognitive decline is unclear.

Researchers started a retrospective study to investigate how glymphatic function in patients with Parkinson’s disease (PD) with mild cognitive impairment (MCI) who progressed to dementia (PDD) compared to those who did not and to see if it could predict who might develop dementia.

They conducted a study with 64 PD patients meeting MCI criteria, categorized as converters (n=29) or non-converters (n=35) based on dementia development during follow-up. Thirty-five age- and gender-matched healthy controls (HC) were also included. Analysis of bilateral diffusion-tensor imaging (DTI) along the perivascular space (DTI-ALPS) indices and volume fraction of enlarged perivascular spaces (EPVS) in centrum semiovale, basal ganglia (BG), and midbrain was compared across groups. They examined correlations between DTI-ALPS index, EPVS, and cognitive performance, alongside investigating EPVS mediation effects on DTI-ALPS and cognitive function.

The results indicated that PDD converters scored lower executive cognitive domain scores than non-converters (P < 0.001). Additionally, PDD converters showed significantly reduced DTI-ALPS index in the left hemisphere (P < 0.001) and increased volume fraction of basal ganglia perivascular spaces (BG-PVS) (P = 0.03) compared to healthy controls (HC) and PDD non-converters. Lower DTI-ALPS index and higher BG-PVS volume fraction correlated with poorer global cognitive and executive function performance. However, no significant mediating effect was observed. Receiver operating characteristic analysis demonstrated that DTI-ALPS effectively identified PDD converters, achieving an area under the curve (AUC) of 0.850.

Investigators concluded that measuring DTI-ALPS, which reflects reduced glymphatic activity, could be a non-invasive way to identify patients with Parkinson’s at high risk of developing dementia.

Source: link.springer.com/article/10.1007/s00415-024-12525-8